pre construction blog

Blog posts
: "General"

BIM Influence on MEP Design Workflow

Critical to effective construction, MEP (M&E or mechanical, electrical, plumbing) design is both one of the key features of a structure and also the one design feature that most people don’t want to deal with, unless something goes terribly wrong with any particular aspect of it. This makes it all the more important to make MEP design as precise as possible. Over time, MEP design has improved and evolved in many ways, but with the arrival of BIM (Building Information Modelling) technology, MEP design has seen modifications in its workflow as well. The workflow of MEP design has been significantly influenced by BIM technology, specifically the roles of the MEP designer and the MEP contractor.

Currently, there are five different MEP design workflow scenarios that exist. They are as follows:

Traditional 2D design and 3D BIM coordination

3D MEP design and 3D BIM coordination

Designers 3D BIM design and coordination

Contractor 3D BIM design and coordination

General contractor 3D model coordination

It is the third workflow that Is becoming increasingly popular. Let’s look at why that is so.

Designers 3D BIM MEP Design and Coordination

This MEP design workflow method is a direct consequence of BIM and promotes the benefit of BIM more significantly, as it gets closer to the ‘virtual design and construction’ aims of the industry. In this workflow, the approach of the design engineer is to create a BIM model that is spatially coordinated, using the actual specified components for the project. Typically, the consultant during this phase will have more time to create the model, allowing him to absorb the changes from structural and architectural disciplines as they progress through the detailing stages. Since the model is then coordinated with the structure and architecture as well as other MEP services, the consultant can create a model according to installation standards and which is more usable by an installer or fabricator.

When the model in this workflow method is passed on to a contractor, the contractor may still wish to make final changes and adjustments in a round of value engineering. Typically, the contractor will use the same model in this workflow and make changes to the model provided by the MEP design consultant. Additionally, it is probable that the consultant engineer will not have provided invert (height) levels or dimensions from gridlines and walls for the MEP services on his drawings. In such cases the contractor will therefore have to create more detail in the drawings, but again, the contractor could use the consultant’s drawings and progress them in more detail for his/her use. This design workflow will require competent BIM coordination and MEP modelling teams and resources. XS CAD, with its large MEP coordination team and MEP engineering design team, which consists of mechanical and electrical engineering professionals, is well placed to deal with such projects for companies based in the USA, UK, Canada, Australia and New Zealand. As all are regions where BIM is now the preferred solution, XS CAD, with more than 16 years’ experience and a presence in each market is an ideal option for such companies.

Lighting design plays a key role in commercial buildings which are typically used by people to perform a task or conduct an activity. To achieve their tasks or activities in a workspace, the right amount of illuminance is necessary, over-lighting is as much as a hindrance to accomplishing tasks as under-lighting. Commercial lighting compared to industrial or residential lighting involves higher initial costs, higher maintenance, longer durability and lifespan and higher service costs. To identify the illumination level requirements or lux level requirements of a commercial building, it would be useful to understand the units of measurement of illuminance, the intensity or amount of light and the efficacy of the relationship between lux and lumen.

Illuminance or lux is the intensity of the level of light and ‘luminous flux’ or lumen is the amount of light produced. Lux is the unit of measurement usually measured in foot candles, one lumen is the measurement of the intensity of the light output and is equal to one lux across an area of one square meter. Given an area you may need to illuminate, the measurement of lux helps you identify the output or lumen required. Typically, for an office which is brightly lit around 400 lux of illumination is required and an office space which uses 100W incandescent bulbs in ceiling panels would produce 1600 lumens as the output of light. When a lighting design company designs light fixtures for a large commercial area, the number of light fixtures is usually increased to get higher lumen keeping in mind the lux level requirements.

A primary factor in ensuring efficiency in light design is achieved by balancing lux and watts or managing the amount of power used to produce light. The measurement of energy efficiency or the power required for light fixtures (luminaires) to operate is known as watts or wattage. The rate at which a light fixture converts power to light or watts to lumen is known as luminous efficacy and measured in lumens per watt (LPW). Typically, an office or commercial space with ceiling panels which would use 32W T5 or T8 fluorescent lamps would usually produce 50 lumens/watt.

Lux level requirements are calculated to determine the appropriate number of lights, the type of light fixtures and the best possible commercial lighting solution, based on the size of the office or commercial space, the type of task or activity which will be conducted and the energy efficiency standards required.

In most cases, based on the client requirements of lux levels, office spaces are over-lit and are usually more than rates mentioned in the lighting standard codes and guidelines developed by professional lighting bodies. Lighting consultants and MEP engineering design teams while keeping in mind client requirements must also consider lighting codes and guidelines which mention the minimum lux level requirements that need to be maintained. Several lighting professional bodies have published handbooks and guidelines, some of which include lighting guides published by the Chartered Institution of Building Services Engineers (CIBSE) in the UK, the IESNA Lighting Handbook by the Illuminating Engineering Society of North America and guides and lighting codes provided by the Lighting Council Australia.

To improve energy efficiency and reduce consumption, several countries have presented lighting codes and green building solutions which have made lighting manufacturers develop higher energy efficient light fittings. For offices and commercial spaces, the stipulated lighting watts/m2 is considered to be within the range of 10 to 15 watts/m2. With the increase in the use of LED light fixtures, lighting consultants are required to maintain lighting watts within the range of 5 to 8 watts/m2, while maintaining lux level requirements.

To ensure commercial lighting designs provide higher energy efficiency, lower energy consumption and better control on energy usage, lighting consultants and MEP engineering design teams must consider trending lighting solutions in the industry. From LED fixtures with advanced lighting controls, energy harvesting technologies, interactive lighting to connected lighting, there are several trends which a lighting design company could use to provide high energy-efficiency and customer-centricity in lighting design solutions for commercial spaces.

In the MEP environment, a building’s MEP designs are initially developed at high level and then detailed to make them clash free and installation ready. MEP designers/consultants play a significant role in design decisions, construction planning, cost estimation and documentation. While design development is typically the role of the consultant and design detailing is done by the MEP contractor, when using MEP (M&E) BIM models and Revit BIM libraries, contractors invariably need to make changes to the MEP design model created by the consultant.

To make a design installation ready, contractors may have to make several changes to the design-intent such as resizing of ducts, re-routing of pipework, adding wall penetrations, bolt locations and datum points for hangars and changing equipment. Once these changes are made by the contractor, the design would be installation ready and will need to be approved by the MEP consultant. The question that this article seeks to answer is why do MEP contractors need to make these and other changes to MEP design models?

• To adjust invert elevations – During the installation of plumbing or drainage pipes, MEP contractors deal with the point of the bottom inside of the pipe, this is known as the invert elevations. To guide pipe design and match the invert elevation height, elevation information can be vertically adjusted at the centre of the pipe using Revit. However, if you are unaware that the elevation information is in centre of the pipe, it could cause confusion in adjusting invert elevations and create discrepancies while coordinating with other disciplines. This is the reason why MEP contractors need to manually adjust invert levels, create spot elevations for the inside bottom of the pipe and change the design models to install pipes which are coordinated with other disciplines.

• To retrofit MEP systems into a prefabricated module environment – Planning for prefabrication of MEP components into the 3D model would not be considered by designers and therefore the contractor is the party who will make adjustments to services to allow them to fit into prefabricated modules to maximise the advantages that are gained from off-site fabrication. In several MEP projects which require prefabrication of risers, ceilings and plant room areas, MEP services drawings and modules specifically for fabricators and installers is necessary to facilitate proper installation. MEP contractors make changes in the MEP design model to ensure that services fit within modules within the ceiling or riser space to allow prefabrication of MEP components off-site allowing faster installation on-site.

• To facilitate efficient spatial coordination – When installing MEP systems, effective spatial coordination with other building services and disciplines is imperative. A consultant may leave clashes in a model as his focus will be on getting a design issue by a due date. A contractor is more concerned with actual fitting so after conducting a clash test on the 3d model, MEP contractors will invariably change design models to ensure that all services are not clashing. The installation programme of the MEP system depends on clash free layouts and MEP contractors must make sure that MEP systems are spatially coordinated with other disciplines in the 3D model before creating M&E (MEP) Coordinated Drawings.

• To deal with constructability issues – There are several factors that influence the constructability or sequence in which MEP systems are installed. Some of the conflicts that require a change in MEP design include routing, fitting and sequencing of large equipment within a given space, conflicting piping network and installation of MEP systems within a crowded space. As MEP contractors need to tackle several conflicts and constructability issues before installing MEP systems, a change in MEP design usually occurs.

• To install MEP systems economically and efficiently – While the MEP design intent may seem to be perfectly coordinated, it need not necessarily be economic or efficient when it involves installation. There are several costs involved when changes need to be made after installation such as re-routing pipes to reduce bends, re-positioning ducts to allow supply and extract in the correct locations, changing equipment or adding wall penetrations, bolt locations and datum points for hangars. To make sure that MEP systems are installed economically and efficiently, MEP contractors must make changes to MEP design models.

• Changes in materials and components – In some cases the MEP model from a consultant is accurately modelled with specified parts, materials and components. However, in some cases projects do not have specified parts and a consultant may use library elements from Revit leaving the contractor to update the model using his planned procurement schedule. This will result in changes due to sizes and access requirements for new components such as a change from copper to plastic pipe which is thicker or a change from one set of pumps to another that may be larger and may have different valve arrangements. The knock-on effect of such component changes can mean that other systems also need to be changed.

Given the many reasons why MEP contractors need to change MEP designs and with the adoption of MEP (M&E) BIM practices, there is an overlap in the scope of MEP contractors and consultants during the planning phase. To know more about how you can reduce the duplication of efforts, additional costs, manage project schedules and reduce scope overlap, read more in this post to find out the possible routes that can be taken.

To ensure MEP design models are installation ready for MEP contractors to use on site, a viable solution would be to work with a 3D BIM coordination specialist or MEP engineering design service provider. At XS CAD, our experienced team of MEP designers in India provide BIM support and spatially coordinated building services drawings for key stakeholders in the MEP (M&E) industry, from MEP (M&E) consulting engineers and MEP (M&E) building services contractors. In our spatially coordinated MEP building services models, we use the latest 3D MEP (M&E) modelling software (Revit MEP) and clash detection technology (Autodesk Navisworks) to provide 3D M&E (MEP) coordinated drawings which adhere to engineering standards, the structural and architectural elements within a building.

The increase in buying power due to access to credit, lower interest and the increase in disposable income, has led to an increase in demand for housing in the homebuilding industry. Buyers now demand custom built homes and home design options according to their requirements and budget. To remain competitive in the market, as homebuilders you must address the challenge of meeting these demands and provide several home design options to buyers.

The inevitability of providing home design options has led to a key challenge of creating construction drawings for houses on each design option variation. Every home design option must be reflected in the construction drawing sets including the elevations, sections and plans. This leads to several challenges from dealing with issues of space when redesigning, maintaining variations of several drawing sheets, difficulty in modifying 2D drawing sets, adherence to building code requirements and the lack of experienced resources.

The Challenges of Incorporating Home Design Option Changes

Whether you are a homebuilder, architect or designer, changes in home design options present several challenges. When incorporating design option changes in residential construction drawing sets, some of the challenges you must consider include:

1. Dealing with issues of space – To accommodate additional design options, in a few cases there is an issue due to lack of space. When redesigning, you need to optimally utilise space to incorporate design options, whether it is adding a garage or porch, making windows and doors bigger or widening a living room space.

2. Maintaining variations of several drawing sheets – To accommodate home design options, you need to create variations of residential construction drawings. A separate drawing is required when you add a space or modify an existing one, this leads to maintaining variations of additional sheets for one design making rework time-consuming.

3. Difficulty in modifying 2D drawing sets – When compared to working with 3D models, 2D drawing sets which are still used, pose a challenge in detecting flaws and coordinating changes. Given the accuracy required to incorporate changes in design options, you need to have precise 2D drawings to make modifications, or it could possibly cost you the time, money and resources invested in the project.

4. Lack of experienced resources – To identify the best possible approach when incorporating home design option changes, an experienced team of Revit technicians is necessary. To accommodate design option changes efficiently and cost-effectively, experienced designers are required and the lack of available resources could be a challenge.

5. Adherence to building code requirements – In home design and redesign, there are several building code requirements that are considered such as standards for size, structure, usage, wall assemblies, floor assemblies, roof structures, mechanical, electrical and plumbing, lighting and energy efficiency standards. A change in home design such as widening a living room space could impact other design elements such as the width of staircase, which may not meet building code requirements and therefore would require complete redesign making it a challenge.

6. Keeping pace with new building requirements and trends – From energy saving designs to home automation, there are new building requirements and trends which you must consider when designing homes. Home designs today must be created keeping in mind trends and requirements such as designing homes which are high on energy efficiency and low on consumption or designs which accommodate home automation devices. Keeping pace with home design trends and requirements when incorporating home option changes could be a challenge.

Given the challenges in incorporating home design option changes, some of the ways in which you can deal with design changes include involving key project stakeholders to facilitate better project management, using database-driven applications to ensure accuracy, managing libraries to maintain several drawings and changes and utilising an experienced team.

At XS CAD, our design team provides documentation and production drawing services for new home designs and new plan updates and 3D interactive plans which allow users to view design options for a selected house design. We work seamlessly with local project teams to provide customised construction drawings for houses, according to design options selected by buyers, and provide a consolidated construction drawing set with all design options incorporated. You can cost effectively utilise our dedicated team of experienced designers to get customised residential construction drawings for design option variations, according to the requirement of your buyers in order to stay competitive in the homebuilding industry.